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Thread: Few questions about my Coupe

  
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    Toms1989's Avatar
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    Few questions about my Coupe

    Afternoon all

    Recently got a Coupe with the Z20LET in it.

    Just a few questions...

    I have a boost gauge on it, Its overboosting to about .6 of a bar and settling to somewhere like .55 or .5 of a bar. Is that about right for a completely bone stock LET?

    I've only put my piperX panel filter in it at the moment, and was wondering if its worth de restricting the box and fitting my vectra pipe to the car? would I see much of a gain at all?

    I was also looking at my Turbo, and its got like a goldy brassy coloured actuator on it, never seen one of these on a LET or LEH? Does it sound like its been changed at all? Also if I want a precat pipe, what would I have to do? as its all one piece on the coupe It looks like.

    Nooby questions I know, but forced induction isn't my area
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    Standard boost is 8-9 psi so I'd say that's about right.

    De-restricting doesn't make a lot of difference but if you've got the airbox off I'd say might as well do it. Vectra C intake doesn't give gains as such, but gives a deeper noise and better throttle response.

    As for the pre-cat. You'll have to get a main cat to bolt on with it. You can get this from a gsi or vxr or buy a sports cat. Sports cats are good for say 5bhp max but are quite pricey.

    I'd say source a good vxr cat section as these are 2.5 inch as standard compared to 2.25 inch found on the mk4.

    Take a picture of the actuator. It could be different but I'm sure some of the newer z20let replacements were golden in colour. Did you get any paperwork with the car - that's how I found out mine had been done.
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    Quote Originally Posted by Will2k1 View Post
    Standard boost is 8-9 psi so I'd say that's about right.

    De-restricting doesn't make a lot of difference but if you've got the airbox off I'd say might as well do it. Vectra C intake doesn't give gains as such, but gives a deeper noise and better throttle response.

    As for the pre-cat. You'll have to get a main cat to bolt on with it. You can get this from a gsi or vxr or buy a sports cat. Sports cats are good for say 5bhp max but are quite pricey.

    I'd say source a good vxr cat section as these are 2.5 inch as standard compared to 2.25 inch found on the mk4.

    Take a picture of the actuator. It could be different but I'm sure some of the newer z20let replacements were golden in colour. Did you get any paperwork with the car - that's how I found out mine had been done.
    Thanks for the detailed reply bud, much appreciated

    I did get a bit of paperwork but nowt with the turbo as I asked. All cam belt stuff had been done, tensioners and idler pulleys, and water pump aswell.

    I did some digging around, with MOT numbers and from 2006-2008 it did say it smoked under load, but then 2009 and 2010 haven't said anything, and were done at the same garage too, and it doesn't look old or in too bad condition.



    Any ideas?
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    defo de-strict the airbox and fit your veccy air take, i noticed a difference with mine. you want to get a solid boost pipe aswell

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    Looks painted... prob to match car.
    Pre cat... i got mine from regal...£160.00 i think.
    in the kit u get an extra flange for your cat section.
    Pre cat has to be cut off.
    I got an exhaust fabricator to cut and tig weld flange on, cost 60 cash for the work.
    Or, buy a cheaper one, about £120.00. the visit the guys at Cobra exhausts.
    Get a s.s 200 cell sports cat for under £300.00.
    In total, if fitn yourself, parts Will be Aprox £450.00.
    Then after that, a cat back system which will be around £300.00 (cobra)
    Total vauxhall fitted there system onto the mag coupeturbo

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    That looks like a standard actuator, I think it's a one of the later ones so no worries there. As for the pre-cat, they are all the same tbh so may as well look out for a used one for around £70. With the vxr main cat and fittng yourself it can be done for under £200 before selling your standard one.

    All looks fine under the engine bay so you should have no worries
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    Pre-cat decat....
    Someone selling one in classified adds in here.
    £100.00
    Decat welded to cat.
    No harm in askin about it

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    Well I've just done the box and fitted veccy C pipe and has made a difference to be fair. Much smoother pull.

    THink I will get a cat back exhaust for now, and keep an eye out for a 2nd hand precat and cat pipe.
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    I had the same all in one piece on my Coupe, Picked up a standard CAT section from a VXR off of VXRonline, there is usually plenty going as one of the main mods is to change the exhaust etc. Paid £30 for mine, people never really want much, I see complete standard VXR exhausts going on there for about £50-60 at the time, then £70 for a milltek pre-cat decat. Then fitted it myself. Job's a good'un!
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    Not bad that coupe2t! cheers for the reply

    Also I've noticed on idle the car has a slight miss, it will idle smoothly and you hear the car puff almost, does it inconsistently

    Any ideas?
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